I tore my ACL a few years ago(5ish) then again about 6-8 months later. I wasn't so into skiing at the time but I was competing nationally in gymnastics, so it was my entire life so I definitely feel ya. It definitely sucks not being able to do the shit you love.
At the time I worked my ass off on other areas of my body(arm, core, etc). Depending on how much you care about those parts of your body, I'd say workout those. It helps to keep you active and not sitting around getting depressed about things.
Also, if you're not into working out, I'd highly, highly, highly recommend focusing on school(if you're in school). Seriously, it's a great time to take a step back and focus on your other main priorities. I was only in middle school at the time so I didn't really do this, but if it were to happen again(I pray it doesn't) I would probably be doing that.
To help the recovery process, I recommend eating an extremely healthy diet. Many people overlook it but it'll speed up healing and it makes you less depressed about not being able to do what you love. Do what they tell you in physical therapy and push yourself without going too far. Ex. Once they tell you that you can do something, take full advantage of it. Ease into it, but don't stop pushing yourself.
Best of luck girl! I promise you'll come out of this with a stronger knee and you'll be able to kill it out there better than before!